Machine and method for the edgegluing of strip stock



A. F. EDERER ETAL April 30, 1957 2,790,483

7 MACHINE AND METHOD FOR THE EDGE-GLUING OF STRIP STOCK Filed June 25,1954 4 Sheets-Sheet l INVENTORS Arthur E Ederer y Bernard A. PearsonApril 30, 1957 A. F. EDERER ETAL MACHINE AND METHOD FOR THE. EDGE-GLUING0F STRIP s'rocx Filed June 25, 1954 4 Sheets-sheaf. 2

INVENTORS Arthur F. Ederer Bernord A. P arson April 30, 1957 A. F.EDERER ETAL ACHINE AND METHOD FOR THE EDGE-GLUING OF STRIP STOCK 4Sheets-Sheet 3 Filed June 25, 1954 n Mm wV T8 e mE V v NF A I rd mw r IA 2y Ber April 30, 1957 A. F. EDERER ET AL 2,790,483

MACHINE AND METHOD FOR THE EDGE-GLUING OF STRIP STOCK Filed June 25,1954 4 Sheets-Sheet 4 veneer- INVENTORS Arthur E Ederer y Bernard A.Pearson v-M MACHINE AND METHOD FOR THE EDGE- GLUING F STRIP STOCK ArthurF. Ederer and Bernard A. PearsomSeattie, Wash, assignors to EdererEngineering Co., Seattie, Wasln, a corporation of Washington ApplicationJune 25, 1954,-Serial No. 43?,406 20 Claims. (Cl; 154-42) This inventionrelates to'a machine and method for the edge-gluing of strip stock.Finding perhaps its greatest usefulness in the plywood industry, thepresent invention is especially advantageous as a means of producingwide strips of face veneer, relatively free of imperfections, fromselected multiple narrow strips which have been so cut from theelongated ribbon taken from a peeler leg as to remove pitch pockets,knots, checks, cracks and other blemishes. These imperfections areperforce objectionable in veneer which is to be exposed to view. Withinthe plywood industry, by reason of the unusually low cost at whichveneers can be edge glued with the present machine and method, thepresent teachings further lend themselves to the production of wide orlong panels of veneer for core or cross banding usage. In allied fields,suggested uses to which the machine and method of our invention may beput are the edge gluing of thin hard board, core board, glass fiberlaminates, paper laminates, container board and the like. In order tosimplify and at the same time give utmost clarity to the followingdescription and claims, the material being worked will be referred tothroughout as Wood veneer but this term is to be interpretedliberally'as comprehending Within its meaning all applicable materialsincluding but in no sense limited to those which we have hereinspecifically named.

In the more accepted techniques, edge-gluing of strips of wood veneer isperformed in one of two ways. One such procedure involves the use of arotating heated cylindrical drum. A succession of veneer strips havingtheir edges coated with glue edge of a following strip against thetrailing edge of a preceding strip, are carried circumferentially ofthis drum while being drawn tightly against the surface. This systern isexemplified by the Miller Patents Nos. and 2,290,762, issued July 21,1942. The other method of edge-gluing veneer strips is commonly termedstraightline gluing, straight in the sense that the path travelled bythe strips in course of being bonded edge-toedge is approximately planaras distinguished from the arcuate path prescribed by acylindricalplaten. The systems shown in the Bolling Patent No.2,398,353, issued April 16, 1946, and in the Carlson Patent No.2,544,133, issued March 6, 1951, are examples of straight-line gluing.Straightine gluing is generally considered to be the more preferredsystem and the machine and method of the present invention, in its broadaspect, is of this type.

For its general object the present invention aims to provide a machineand method for the edge-gluing of veneer which completely obviates gapsand overlaps along the line of joinder, even with the very-thinneststock, and I which attains a speed of output far exceeding that whichhas been considered possible with any of the machines and methodsheretofore known. p

it is perforce the object of all edge-gluing machines-to have theabutting glued edges of two adjacent 'stripsex-actly register during theperiod necessary for the glue to and crowded,- the leading United StatesPatent V i 2,790,483 P atent ed Apr. 30,

2 set, and this desired result iscomplicated the factlthat the strips,being usually very thin, undulate to a considerable extent, particularlyalong the edges, These W aVes:

obviously are not uniform, hence the meeting edges of two adjacentstripsare normally out of registration; As

one of its objects the present invention, in. orderto bringthese edgesinto registration, aims to provide a system giving continuous travel tothe strips along a defined generally planar travel path and in course ofsuch travel forcefully" distorting the strips in such a manner as tosubstitutefor the local variables a constantly changing controlled wavemade to conform to an established pattern so that the edges which are tobe joined are ,placed and, held; in perfect registration during theperiod necessary to consummate a secure bondingtherebetween Theinvention has the still further and important object of devising anendless conveyor for the veneer strips ,ef-

sure whileothers call for cooling. The present inventionmay, if desired,use glues of this nature'butwe prefer to employ a thermo-settingadhesive, examples of which are urea'formaldehyde, resorcinformaldehyde,phenol formaldehyde, plastisols, starches and silicates, and it is afurther particular object of the invention to provide a sys-' ternwherein infra red rays serve as the heat medium for setting the glue,and wherein the design'of theconveyor peculiarly lends itself to suchheating rays in thatit perniits the infra red rays to operate with amaximum efficiency, the invention, in consequence of its ,use ofinfrared rays, accomplishing setting of the glue in a considerablyshorter time than has been possible with machines and methods heretoforeknown.

A yet further object of the invention is to provide a system in whichthere is made to act uponthe conveyed strips in course of their conveyedtravel and'following the latters traversal of the heating means acoolinginst rumentality' which operates to rapidly dropthe temperature of theglue-bonded strips.

The foregoing, with still additional objects and an,

vantages in view looking especially to the provision of a machinegenerally more efiicient, one which by comparison with existing machinesis considerably less expensive to build, and one which requires for its,operation and maintenance only a minimum-of attention, will appear andbe understood in the course of the following-- description and claims,the invention consisting in the.

novel method andin the construction, adaptation and combination of theparts ofa machine for practicing said method hereinafter described andclaimed;

In the accompanying drawings;

Figures 1 and2 are fragmentary side elevational-views which, takentogether, illustrate a completemachine constructed to embody thepreferred teachings of the present invention. The first said view, moreespecially portrayst the crowder table, which functions -to press the'leading edge of a following veneer strip hard against the trailing edgeof a preceding veneer strip, together'with the fore portion of that partof the machine responsibl'e for impressing a-wave pattern into thetravelling-veneer strips and at the same time setting the glue byeinfrared heat.-

The latter 'saidview portrays theaft portion of said wave heatingpart ofthe machine together with the cooling table.

.Fig.- 3- is a fragmentary enlarged scale longitudinal-vei'= ticalsectional view of 'a -head--endportion ofthe' machinef theview being.-somewhat' schematic in-="that the'irimiwork is largely deleted.

Fig. 4 is a fragmentary longitudinal vertical sectional view of thecooling table, the scale employed corresponding to that of Figs. 1 and2.

Fig. 5 is a fragmentary transverse vertical sectional view drawn to anenlarged scale on line 55 of Fig. 4.

Fig. 6 is a large-scale schematic view portraying the manner in whichsuccessive pressure-exerting rolls are moderately staggered to causetravelling veneer strips to travel a sinusoidal path in moving from thecrowding table at one end to the cooling table at the other end of themachine.

Fig. 7 is a fragmentary transverse vertical sectional view drawn to anenlarged scale on line 77 of Fig. 3; and

Fig. 8 'is'a fragmentary transverse vertical sectional view on line 8-8of Fig. 3.

Reiterating that which has been previously pointed out, veneer strips,being usually very thin, tend to bend or wrinkle in consequence ofinternal stresses usually attributed to non-uniformity of moisturecontent and, to a lesser extent, to variations in the graining of thewood. This wrinkling is perforce quite irregular and becomes especiallypronounced along those side edges of the strip which run longitudinallyof the grain. These are the edges which are bonded together when veneerstrips are glued edge-to-edge, but excepting for the Miller machineswith their cylindrical platens, and which have a slow speed and hencegiven an objectionably low output, there has not been heretofore devisedany effective continuousoperation machine that will positively bring themeeting edges of two abutting strips into exact registration. Carlsoncan perhaps be credited with having visualized that,

the edges might be brought into registry if, in lieu of subjecting saidedges to the force of a heavy ironing pressure, there is producedthroughout the length of the said edges an internal stress having itsresponsible force of sufficient intensity to override the localstresses. To attain this theoretical end Carlson impresses upon themeeting edges of the veneer a bowed configuration, the bow being asingle curve running end to end of the concerned edges. In Carlson thecreation of this bend must hence be accomplished very gradually in thatsuch a long bend, to be effective, must have appreciable magnitude,amplitude considered. Moreover, where a long bend of major amplitude isimpressed upona veneer strip the impressed wave must be thereafterforcefully erased, all of which means that the output from a machineembodying the teachings of Carlson is little better than that of theMiller machine. The findings of the present invention are that only asimple harmonic wave representing a summation of sinusoids which runlongitudinally of the grain, and of only moderate amplitude, need beimpressed upon the veneer strip, and that glue coating the meeting edgesof two abutting strips can be set in a comparatively short period oftime where such edges are subjected to infra red rays.

Clarity in an understanding of the nature of the invention will perhapsbe advanced by here stating that the apparatus for practicing theinvention comprises, in general, a procession of conveyors onto whichveneer strips, having firsthad glue applied to one or both of the sideedges thereof, and namely the edges which run longitudinally of thegrain, are delivered with said coated edges extending transverse to thepath of travel. Such delivered strips are conveyed by the conveyorssuccessively, first traversing a crowding zone wherein, as the wordimplies, there is performed a crowding action causing the leading edgeof each following strip to be pressed hard against the trailing edge ofeach preceding strip, then traversing a processing zone wherein thecrowded strips are subjected to a waving action while beingsimultaneously brought under the glue-setting influence of infra redrays, and finally traversing a cooling zone wherein the heat of the.glued strips is rapidly dissipated.

Referring to the drawings it will be seen that there is provided asuccession of three conveyors which will be hereinafter referred to asthe crowder conveyor, the processing conveyor, and the cooling conveyor.The crowder conveyor is composed of complementing upper and lowermembers comprised, as respects the upper member, of a plurality oflaterally spaced endless belts 10 passing about live and idler rollers11 and 12, respectively, and, as respects the lower member, of aplurality of laterally spaced endless belts 13 passing about live andidler rollers 14 and 15, respectively. The processing conveyor issimilarly composed of complementary upper and lower members and eachsaid member is likewise comprised of laterally spaced endless belts, as16 and 17, but in the instance of the processing conveyor belts thematerial of which the belts are composed is metal, high carbon steelbeing suitable, butt-welded to form an endless band, whereas noparticular significance is attached to the material composing the belts10 and 13. Said upper and lower processing belts are each supported by arespective pair of driving and driven shafts, as 2021 and 22-23, and afeature of the invention is that the upper said shafts 20 and 21 admitof being set in vertically adjusted positions, thereby to vary thespacing between the lower run of the upper and the upper run of thelower set of bands. Such lower shafts 22 and 23 have their endsjournaled in a stationary lower frame 24. The upper shafts 20 and 21have their ends journaled in an upper frame 25, and for the purpose ofadjusting said upper shafts vertically such upper frame at each of itsfour corners presents a bearing disc 26 seating upon the lower frame.These discs connect with the upper frame by eccentrics 27 journaled inthe frame and'have protruding ends thereof splined or otherwise rigidlyconnected to regulating arms 28, the free ends of such regulating armsbeing adjustably secured by knurled nuts 29 to frame-carried quadrants30. In each side of the upper frame at the tail end thereof there isprovided a vertical slot 31, and in each side at the head end there isprovided a horizontal slot 32. Pins 33 and 34, respectively, which arecarried by the lower frame lodge in these slots. Slots 31 and pins 33perforce serve as guides holding the tail end of the upper frame tomovement in a fixed vertical plane, with expansion and contraction ofthe frame being compensated by the horizontal nature of the head slots32. It will be understood that the purpose in varying the spacingbetween the complementing runs of said two sets of processing bands isto accommodate the machine to different thicknesses of the veneer stockbeing run.

As here illustrated the two driving shafts 2i) and 22 lie at the tailend of the processing conveyor while the driven shafts lie at the headend, and provided on each such shafts and keyed, pinned or otherwiserigidly secured thereto are respective sets of wheels, as 35 and 36,there being one such wheel for each end of each metal band. The severalWheels in each set are placed at uniformly spaced intervals, and suchwheels are staggered so that those carried by each upper shaft occur inthe intervals midway between those carried by each lower shaft. Whilenot illustrated the several wheels 35 are each crowned to resistcreeping of the bands in a direction endwise to the axis of rotation ofthe wheels, and for a similar purpose, adjacent the wheels 36, there areprovided fair-lead rollers 38 hearing against opposite sides of eachband along the upper run of the upper and along the lower run of thelower set of conveyor belts. Bell-crank levers 49 fulcrumed, as at 41,to the upper frame 25 adjustably carry a weight 42 on one of the twoarms thereof. The other arm carries a roller 43 which is pressed by saidweight against the respective band 16 for tensioning the latter, and atopposite sides of this tensioning roller are yoke arms 44 giving supportto the fair-lead rollers. Much the same fair-lead and tensioningarrangement is provided for the bottom bands 13 excepting that in thisinstance a plain lever 45 is employed so that force of 6 gravity actingupon the weight 46 urges the tensioning roller 47 in an upwarddirection. I

Journal-mounted by their ends in said upper frame to bear from aboveupon the lower runs of the upper bands 16 are sets of longitudinallyspaced apart transversely extending pressure rolls and longitudinallyspaced counterparts of these transverse rolls, denoted by 51, arejournal-mounted by their ends in the lower frame so as to hear frombelow upon the upper run of the lower bands 17, the placement of suchlower pressure rolls being such that the same occur in the intervalsmidway between the rolls 59. While not here illustrated, journal boxes52 for these several pressure rolls admit of being adjusted individuallyrelative to the related supporting frames, but no need arises forchanging the adiustment thereof after the same have been once set inthat the only adjustment thereafter required is that given to the upperframe, causing the rolls 50 to be raised or lowered bodily in unison. Tothe immediate front of each pressure roll and carried by the upper frame25 or by the lower frame 24, as the case may be, is a respective trayofinfrared tubes 53 such, for example, as the Merco tube illustrated anddescribed in U. S. Pat. #2535168. Each tube has a reflector 54 focusingits produced heat rays onto edge-abutted veneer strips conveyed by theprocessing conveyor. In each tray there are preferably three of saidinfrared tubes, each of 4000 watt capacity, and in our machine as it ispresently engineered there are ten of these trays, five above and fivebelow the travel path of the conveyed veneer strips, in a processingzone having an overall length of approximately 20 ft. It is desirablethat the trays in each row be spaced more or less equidistantly apartand that the trays of the lower series be staggered with respect to thetrays of the upper series to have the lower trays occur in the intervalsbetween upper trays.

It is to be particularly noted that all ten trays are required only whenthe stock being run is unduly thick or when the strips are beingconveyed at a very rapid speed. By way of example, We find that onlyfive trays of the infrared tubes need be activated in the edge-gluing ofA fir veneer stock travelling at a conveyor speed as high as 28 F. P.M., this being, in the present machine, a ceiling speed dictated by therapidity at which the glued strips may be fed by hand to the crowderconveyor. While a 28 F. P. M. output of A edge-glued veneer stock is farin excess of the output possible with any previous machine and method ofwhich We are aware, there is presently being developed, for our machine,a mechanized means of feeding the glued stock which we anticipate willenable us to produce edge-glued veneer at a speed appreciably exceedingthe present high output figures. Further by way of example, eight ofsaid trays of infrared tubes are found sufficient to set the glue on A"fir veneer moving through the machine at a speed of 20 F. P. M.

It has been our finding that adhesives exposed to the same temperaturesas that of our infrared radiation but obtained by convection heatingfrom other sources has a considerably slower curing speed. A probableexplanation is that the infrared waves have a peculiar ability topenetrate into and through the wood, which is an insulating material, orit is quite conceivable that the radiant energy of infrared heatactivates, in some way peculiar to itself, the chemical setting of theadhesive.

.Before proceeding to describe the parts of the machine which functionat complements of said processing. conveyor, let us dwell on onestriking accomplishment possible where the adhesive which is used in theedge gluing of veneers is cured or set by the utilization of the radiantenergy of infrared light rays. Occurring in consequence of an ability ofthe rays to penetrate into and through thewood it becomes possible andpractical, should any need therefor arise, to inactivate all of thetrays either above or below the path travelled by the conveyed stripsaysonss of veneer. Many woods which find extensive usage asface'veneers, pine for example, are prone to discolor under heat andlight, and particular care in the application of heat must ordinarily begiven to materials of this nature when strips thereof are being edgeglued. Using infrared radiation as the curing instrumentality permitsall of the heat to be directed to one face only of the veneer stock,leaving the other face unexposed yet accomplishing thorough setting ofthe glue. The exposed face, which perforce would be concealed in use,might conceivably be almost black yet leave the unexposed facecompletely free of discoloration.

Reverting now to the crowder conveyor, it will be seen that the tailroller 14 thereof lies beyond the head wheels 36 of the processingconveyor, with the upper level of the belts l3 placed to coincide withthe upper level of the bands 17. Longitudinal slats 57 supported bycrossmembers 58 carried by the lower frame 24 firmly sustain saidcrowder belts 13, these slats extending substantially the full length ofthe crowder table excepting for a gap occurring immediately under thehead roller 11 of the .upper crowder belts 10. In traversing this gapthe lower crowder belts are sustained by an idler roll 6t Said headroller 11 and its complementing tail roller 12 are each carried forbodily vertical movement by a floating frame 61 which is guidablymounted at its inner end from the upper main frame 25 and at each sidefrom the lower main frame 24. Said end guides comprise pins 64 workingin vertical slots 65. The travelling speed of the crowder belts isconsiderably faster than that of the proc essing conveyor, and it isthis accelerated speed which performs the function which the namecrowder implies, namely that of causing each of a plurality ofsuccessively fed strips to be overtaken by a next succeeding strip, andsuch following strips to have their leading edge pressed hard againstthe trailing edge of the immediately preceding strip. The floating frame61 is made fairly heavy to hold the upper belts 10 firmly against veneerstrips passing therebelow, thus to insure a positive friction drive, andfor adjusting this Weight a yielding upward thrust is exerted by springs66 against the side guide pins 64.

As regards the cooling conveyor, which extends from the tail end of theprocessing conveyor so as to receive the multi-strip veneer sheetfollowing traversal by the latter of the processing zone, such iscomprised of a plurality of transversely spaced belts 70 passing aboutlive and idler rollers 71-72, respectively. The veneer sheet feeds fromthe processing conveyor onto the upper run of these belts and by thelatter is conveyed between perforated facing plates 73 of two boxes, as74 and 75, one lying above and the other lying below said belt run. Airfor cooling said sheet is delivered under the pressure influence of ablower or blowers (not shown) through ducts 76 to the boxes, issuingthrough the perforations of the plates ontoupper and lower surfaces ofthe sheet.

It will be understood, in setting the upper frame 25, that the pressurerolls 5% carried thereby are brought into such relation to the pressurerolls 51 as will cause the veneer strips conveyed by the processingconveyor to traverse a sinusoidal course, and which is to say follow thepath of a propagating wave. For thin veneers such, for example, as orig" the usual setting places the pressure rolls 50 such that ahorizontal plane tangent to the bottoms is moderately below a horizontalplane tangent to the tops of the bottom pressure rolls 51. The pressurerolls 5t) are raised somewhat for handling veneer strips of greaterthickness. As the successive edgeabutted strips progress along saidsinusoidal path, the pressure from the tensioned bands, exerting forceupwardly and downwardly alternately, upon'the advancing strips throughthe span, on the one hand, between two adjacent lower, pressure" rollsand, onthe other hand, -betu'leen' two adjacent upper pressure rolls, impresses upon such; strips a corrugated shape or, more specifically, atraversing simple harmonic wave running transversely from one to theother side edge of the strips. This wave is represented in Fig. 8. Thegrain of the wood strips runs longitudinally, or approximatelylongitudinally, of the juxtaposed edges. The produced wave is asummation of sinusoids which runs longitudinally of the grain or,otherwise stated, a harmonic pattern of multiple waves in which the zaxes of these individual waves are each at cross angles to thejuxtaposed edges. The Wood strips are maintained in such corrugatedcondition throughout the travel of the strips with the processingconveyor, the time interval thereof being sufficient to substantiallyset the glue.

For imparting to the processing conveyor and to the cooling conveyortravelling movement of corresponding speed and imparting to the crowderconveyor an accelerated travelling speed there is shown a motor 77passing the drive through chains '78 and 79 to a sprocket wheel 86 fastto the driving shaft 22. Respective meshed gear wheels 83 and 82 fast tosaid shaft 22 and to the driving shaft 25) pass the drive from theformer to the latter shaft. While not shown, a chain carries the drivefrom driving shaft 22 to a sprocket wheel fast to the head roller 71 ofthe cooling conveyor. For powering the live tail roller 14 of thecrowder conveyors lower belt 13 a chain 83 passes power to a sprocketwheel 84 from a sprocket wheel 35 on the driven shaft 23. From the livetail roller 14 a chain 86 in turn passes the drive to the live tailroller 11 of the crowder conveyors upper belt 1.9, being tensioned by aspring-pressed idler wheel @7. The motor 7'7 is equipped with a rheostatto adjust its speed so that the time interval required for the veneerstrips to negotiate the processing conveyor may be increased anddecreased for greater and lesser thicknesses of veneer, or for more andless activated heating trays.

The method of the invention, and the machine for practicing same, arethought to be clear from the foregoing. It will be apparent thatmodifications may be resorted to without departing from the spirit ofthe invention and we accordingly intend that no limitations are to beimplied and that the hereto annexed claims be given a scope fullycommensurate with the broadest interpretation to which the employedlanguage fairly admits.

What we claim, is:

l. The method of edge-joining wood veneer strips having a grain runninglongitudinally of the edges which are to be joined, and which comprisesfeeding at least two of said strips one in following relation to theother along a generally planar travel path with the edges which are tobe joined having glue applied thereto and with said glued edgesextending transverse to the course of travel and juxtaposed the leadingedge of the following strip against the trailing edge of the precedingstrip, and in course of such travel impressing upon the juxtaposed edgesa simple harmonic wave running longitudinally of the grain from one tothe other side edge of the strips.

2. The method of edge-joining wood veneer strips having the grainrunning longitudinally of the edges which are to be joined, and whichcomprises feeding at least two of said strips one in following relationto the other along a travel path with the edges which are to be joinedhaving glue applied thereto and with said glued edges extendingtransverse to the course of travel and juxtaposed the leading edge ofthe following strip against the trailing edge of the preceding strip,and in course of such travel impressing upon the juxtaposed edges asimple harmonic wave running longitudinally of the grain from one to theother side edge of the strips.

3. The method of edge-joining wood veneer strips having the grainrunning longitudinally of the edges which along a given travel path withthe edges which are to be joined having thermosetting glue'appliedthereto and with said glued edges extending transverse to the course oftravel and juxtaposed the leading edge of the follow ing strip againstthe trailing edge of the preceding strip, in course of such travelimpressing upon the juxtaposed edges 21 simple harmonic wave runninglongitudinally of the grain from one to the other side edge of thestrips, and while maintaining the said simple harmonic wave upon thejuxtaposed edges applying heat thereto to set the glue.

4. The method of edge-joining wood veneer strips having the grainrunning longitudinally of the edges which are to be joined, and whichcomprises feeding at least two of said strips one in following relationto the other along a generally planar travel path with the edges whichare to be joined having thermosetting glue applied thereto and with saidglued edges extending transverse to the course of travel and juxtaposedthe leading edge of the following strip against the trailing edge of thepreceding strip, in course of such travel impressing upon the juxtaposededges 21 simple harmonic Wave running longitudinally of the grain fromone to the other side edge of the strips, and while maintaining the saidsimple harmonic wave upon the juxtaposed edges setting the glue by infrared radiation.

5. The method of edge-joining wood veneer strips having the grainrunning longitudinally of the edges which are to be joined, and whichcomprises feeding at least two of said strips one in following relationto the other along a given travel path with the edges which are to bejoined having glue applied thereto and with said glued edges extendingtransverse to the course of travel and juxtaposed the leading edge ofthe following strip against the trailing edge of the preceding strip, in

' course of such travel impressing upon the juxtaposed edges a simpleharmonic wave running longitudinally of the grain from one to the otherside edge of the strips, applying heat to said strips to set the glueWhile continuing to impress said wave upon the juxtaposed edges, andthen cooling the strips by passing the same through a zone of agitatedair.

6. The method of edge-joining wood veneer strips having the grainrunning longitudinally of the edges which are to be joined, and whichcomprises feeding at least two of said strips one in following relationto the other along a course generally following the line of propagationof a comparatively flat simple harmonic wave with the edges which are tobe joined having glue applied thereto and with said glued edgesextending transverse to the course travelled by the strips andjuxtaposed the leading edge of the following strip against the trailingedge of the preceding strip, and during such travel impressing upon thejuxtaposed edges a simple harmonic wave running longitudinally of thegrain from one to the other side edge of the strips.

7. The method of edge-joining wood veneer strips having the grainrunning longitudinally of the edges which are to be joined, and whichcomprises giving continuous travel to at least two of said strips one infollowing relation to the other along a course generally following theline of propagation of a comparatively flat simple harmonic wave withthe edges which are to be joined having glue applied thereto and withsaid glued edges extending transverse to the course travelled by thestrips and juxtaposed the leading edge of the following strip againstthe trailing edge of the preceding strip, and during such travelimpressing upon the juxtaposed edges a simple harmonic wave runninglongitudinally of the grain from one to the, other side edge of thestrips.

8. The method of edge-joining wood veneer strips, and which comprisesfirst applying thermosetting glue to the edges which are to be joined,and then moving a succession of said veneer strips along a given travelpath with.

the glued edges extending transverse to the line of progress and incourse of said travel causing each of the strips in turn to be overtakenby the next succeeding strip so as to bring the glued edges intojuxtaposition,.and then directing infra red rays onto the strips forsetting the glue with the rays substantially encompassing the veneerstrips throughout a zone of sufiicient extent, considering the speed atwhich the strips move, as will assure a setting of the glue upon atraversal of said zone.

9. The method of edge-joining veneer strips recited in claim 8 in whichthe sources from which rays issue are located both above and below thestrips as they move through said zone and are staggered as between thesources of infra red rays which lie above and those which lie below themoving strips.

10. A machine for edge-gluing wood veneer strips each of which has itsgrain running longitudinally of the edges which are to be joined,comprising a generally horizontal processing throat defined at the topby the lower run of an upper endless conveyor belt and at the bottom bythe upper run of a lower endless conveyor belt, each of said beltscomprising a multiplicity of parallel uniformly spaced tensioned bandsand with the bands of the one conveyor occurring in the intervals midwaybetween the bands of the other conveyor, and a respective row oftransversely extending longitudinally spaced apart pressure rollsbearing from below upon said upper run of the lower conveyor and fromabove upon the lower run of the upper conveyor and characterized in thatthe rolls of the lower said row occur in the intervals between the rollsof the upper said row, the two rows of rollers being so placed, onerelative to the other, as to prescribe a sinusoidal path for veneerstrips conveyed by said conveyor belts through said processing throat.

11. A machine for edge-gluing wood veneer strips each of which has itsgrain running longitudinally of the edges which are to be joined,comprising a generally horizontal processing throat defined at the topby the lower run of an upper endless conveyor belt and at the bottom bythe upper run of a lower endless conveyor belt, each of said beltscomprising a multiplicity of parallel uniformly spaced tensioned bandsand with the bands of the one conveyor occurring in the intervals midwaybetween the bands of the other conveyor, a respective row oftransversely extending longitudinally spaced apart pressure rollsbearing from below upon said upper run of the lower conveyor and fromabove upon the lower run of the upper conveyor and characterized in thatthe rolls of the lower said row occur in the intervals between the rollsof the upper said row, the two rows of rollers being so placed, onerelative to the other, as to prescribe a sinusoidal path for veneerstrips conveyed by said conveyor belts through said processing throat,and means concentrating heat upon the veneer strips conveyed by saidconveyor belts through said processing throat.

12. A machine for edge-gluing wood veneer strips each of which has itsgrain running longitudinally of the edges which are to be joined,comprising a generally horizontal processing throat defined at the topby the lower run of an upper endless conveyor belt and at the bottom bythe upper run of a lower endless conveyor belt, each of said beltscomprising a multiplicity of parallel uniformly spaced tensioned bandsand with the bands of the one conveyor occurring in the intervals midwaybetween the bands of the other conveyor, a respective row oftransversely extending longitudinally spaced apart pressure rollshearing from below upon said upper run of the lower conveyor and, fromabove upon the lower run of the upper conveyor and characterized in thatthe rolls of the lower said row occur in the intervals between the rollsof the upper said row, the two rows of rollers being so placed, onerelative to the other, as to prescribe a sinusoidal path for veneerstrips conveyed by said conveyor belts through said processing throat,and means directing infrared rays upon the veneer strips conveyed bysaid conveyor belts through said processing throat.

13. The machine of claim 12 in which the means for directing infraredrays comprises multiple reflector backed' trays of infrared heatingunits "located at spaced intervals 14. A machine according to claim 13in which the trays,

admit of being activated selectively so as to use a greater or a lessernumber of said trays in accordance with the nature and speed of theveneer strips being run.

15. A machine for edge-gluing wood veneer strips each of which has itsgrain running longitudinally of the edges which are to be joined,comprising a generally horizontal processing throat defined at the topby the lower run of an upper endless conveyor belt and at the bottom bythe upper run of a lower endless conveyor belt, each of said beltscomprising a multiplicity of parallel uniformly spaced bands and withthe bands of the one conveyor occurring in the intervals midway betweenthe bands of the other conveyor, a respective row of transverselyextending longitudinally spaced apart pressure rolls bearing from belowupon said upper run of the lower conveyor and from above upon said lowerrun of the upper conveyor and characterized in that the rolls of thelower said row occur in the intervals between the rolls of the uppersaid row, the two rows of rollers being so placed one relative to theother as to prescribe a sinusoidal path for veneer strips conveyed bysaid conveyor belts through said processing throat, the strips beingintroduced between said conveyor belts at the head end of the processingthroat with the grain extending transverse to the path of conveyedtravel and with the leading edge of each following strip abutting thetrailing edge of the preceding strip, means being provided for sotensi'oning the bands that said strips have impressed thereon a simpleharmonic wane running longitudinally of the grain from one to the otherside edge of the strips.

16. The machine of claim 15 in which the bands are each comprised of abutt-welded ribbon of metal.

17. A machine according to claim 15 wherein means are provided forbodily raising and lowering the upper conveyor belt and the relatedpressure rolls for adjusting the machine to the handling of differentthicknesses of veneer stock.

18. The method of edge-joining wood veneer strips having the grainrunning longitudinally of the edges which are to be joined, and whichcomprises feeding at least two of said strips one in following relationto the other along a travel path with the edges which 'are to be joinedhaving glue applied thereto and with said glued edges extendingtransverse to the course of travel and juxtaposed the leading edge ofthe following strip against the trailing edge of the preceding strip,and in course of such travel impressing upon the juxtaposed edges a wavewhich represents a summation of sinusoids and which runs longitudinallyof the grain from one to the other side edge of the strips.

19. The method of edge-joining veneer strips, and which comprisesfeeding at least two of said strips one in following relation to theother along a travel path with the edges which are to be joined havingglue applied thereto and with said glued edges extending transverse tothe course of travel and juxtaposed the leading edge of the followingstrips against the trailing edge of the preceding strip, and in courseof such travel imposing upon the juxtaposed edges a wave representing asummation of sinusoids with the z axes of the individual waves beingeach at cross angles to the said juxtaposed edges.

20. The method of edge-joining wood veneer strips having the grainrunning longitudinally of the edges which are to be joined, and whichcomprises giving continuous travel to at least two of said strips one infollowing relation to the other along a course generally following theline of propagation of a comparatively flat wave with the 1'1 edgeswhich are to be jeined havingzglne applied ihereto and? with said gluededges ex tendingn transverse to the donrse-travelledby the strips andjuxtaposed the leading edge of the following strip against the 'trailingedge of the preceding strip, =and'dt1ring such travel impressing uponthe juxtaposed edges a wave which represents "a'summation -of sinusoidsand which runs longitudinally of the -grain"from une 'tothe othersideedge of the strips.-

References'Cit d in the fiie of i this patent UNITED: STATES PATENTSJpnesl. Dec, 4, 1928 Weber' Feb; 12, 1929 Linquist" Apr. 20, 1943Cai'lsQn Mar. 6, 1951 Lun'dberg' Oct. 30, 1951 U1ihschneidet- Feb. 24,1953

